Transition metal complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups.

Using three different approaches, racemic 1-(perfluoroalkyl)ethylamines were synthesized from perfluoroalkyl iodides or perfluoroalkanoic acids, and further transformed to the corresponding N,N'-disubstituted ethane-1,2-diimines and ethane-1,2-diamines as mixtures of diastereoisomers. Their cyclization afforded imidazolium or dihydroimidazolium salts, which led to silver or palladium complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups. The palladium complexes bearing a throwaway 3-chloropyridine ligand proved to be moderately active in the model Suzuki-Miyaura coupling.

[Selenium deficiency of west Bohemia population]. / Deficit selenu v populaci západních Cech.

To estimate status and intake of selenium in inhabitants of the most Western region of the Czech Republic (Cheb region) 241 serum, 404 urine and 30 hair samples from randomly selected persons in the age between 6 and 65 years is performed. Serum and hair samples were analysed by means of instrumental neutron activation analysis (INAA), while Se in urines was detected by means of fluorimetry. Urine iodine was determined in the same group by Sandell-Kolthoff method for the possibility to detect concomitant Se and I deficiency and/or correlations between these two essential trace elements necessary for metabolism of thyroid hormones. Average values of Se indexes are low (55.4 +/- 13.8 microg Se/L serum; 15.4 +/- 5.7 microg Se/L urine; 13.6 +/- 6.0 microg Se/g creatinine; 0.268 +/- 0.051 microg Se/g hair) and prove Se deficiency in the searched population. Statistical evaluation of Se in subgroups of boys, girls, men and women proved significant differences as far as age is concerned, gender differences were found only between boys and girls. Some significant and highly significant differences were found also in subgroups according age and gender (males and females in the age of 6, 10, 13, 18-35, 36-49 and 50-65 years). On the other hand, urine iodine average value (126 +/- 65 microg/L) is on the lower optimum level. By the use of correlation analysis, slight but significant correlations were found between Se and I in urine and some of thyroid hormone parameters and their influence on the organism.

Effect of iodine and selenium upon thyroid function.

Iodine is an essential element with unique role in organism: it is indispensable component of thyroid hormones. After binding with specific nuclear receptor, T3/T4 induce transcription of genetic code via mRNA and regulate proteosynthesis in most tissues. Thyroid hormones regulate rate of metabolic processes and consequently development of organism. Czech Republic was in past typical region with moderate to severe iodine deficiency. Therefore epidemiological survey was started in randomly selected samples of peoples. Thereafter a complex program of improving iodine supply was realized. Prompt effects of this changes were recorded, namely increase of ioduria and decrease of thyroid volume. Essential trace element selenium has a fundamental importance to the cell and body metabolism regulation by thyroid hormones. Activities of selenoenzymes deiodinases lead to the activation of prohormone T4 to active hormone T3 and the inactivation of T3 and of T4, as well. There is unfortunately moderate to mild Se deficit in the CR. Average serum Se concentrations for the populations from 6 to 65 years are in the regions of the CR between 42 and 62 micrograms/l and urine Se values are between 8 and 15 micrograms/l. We have found statistically significant correlations among indexes of selenium status and indexes of thyroid hormone metabolism and function. Especially dangerous are concomitant deficiencies of both key elements for thyroid hormone metabolism--I and Se--from the point of thyroid hormone regulative functions.

[Selenium and the organism]. / Selen a organismus.

Selenium is an essential trace element for animals. It is biologically active as selenocysteine in the active centre of selenoproteins with enzymatic functions. Incorporation of selenocysteine occurs on the basis of genetic expression and selenium is the only trace element under direct genetic control. Selenocysteine can be considered the 21st amino acid with regard to its biosynthesis and incorporation into proteins. At least two types of selenoproteins are necessary for each animal cell, the first from the family of GSH-peroxidases and the second from the family of deiodinases. GSH-peroxidases are the most powerful antioxidant enzymes, which defend the cell and whole organism against oxidative damage and thus from oxidative diseases and disorders such as cardiovascular diseases, malignancies, bacterial or viral diseases, muscle dystrophy, arthropathy, arterial plaques, and others. GSH-Px have many other regulatory functions such as regulation of biosynthesis of prostaglandins, prostacycline, leukotrienes, and thromboxans. Deiodinases regulate the metabolism of biologically active triiodothyronine and thus thyroid hormone regulation of the whole organism. Selenoproteins act against cancerogenic effects of some organic molecules and bind heavy metals. Tissue-specific selenoproteins without a known biological function have been detected in some specialised tissues with a high priority for selenium. One of the regulators of selenoprotein synthesis is the selenium status of the organism. Its state an intake may be assessed by analyses of selenium indexes. The most often used indexes are serum selenium and urinary selenium. On the basis of its analyses in six regions of the Czech Republic, severe selenium deficiency has been found in inhabitants of this country, which is even profound for more distressed groups like growing children, pregnant and lactating women, and the elderly.

Status of magnesium, selenium and iodine saturation in the population of seven regions in the Czech Republic.

In seven regions of the Czech Republic the magnesiuria and calciuria were determined photometrically using the apparatus Merck Vitalab Eclipse, the selenuria fluorimetrically and the ioduria photometrically after alkaline mineralization in the morning sample of urine (after night fasting) in subjects aged 6-65 years (3,587 probands) selected at random. The lowest magnesiuria was found in children in Klatovy district (5.36 nmol/l +/- 0.11) and the highest magnesiuria was estimated in children from the Ustí nad Labem district (6.59 mmol/l +/- 0.16). In adults the lowest magnesiuria was in Vsetín region (3.78 mmol/l +/- 0.08). Selenuria was lowest in Jindrichüv Hradec (7.60 micrograms/l +/- 0.30) and highest in the Vsetín district (15.07 micrograms/l +/- 0.50). Adults had the lowest selenuria in the region Jindrichüv Hradec (7.67 micrograms/l +/- 0.30) and the highest in Ustí nad Orlicí (11.68 micrograms/l +/- 0.34). The lowest ioduria was estimated in children from Ustí nad Labem (94.30 micrograms/l +/- 2.06) and the highest in the Vsetín region (151.60 micrograms/l +/- 7.55). Adults from the district Jindrichüv Hradec had ioduria merely (77.7 micrograms/l +/- 2.18) and the highest ioduria was found in probands from the Znojmo region (123.30 micrograms/l +/- 4.47). As far as the dependence on age is concerned, the magnesiuria significantly decreases both in children and in adults with the increasing age. Selenuria decreases in adults significantly with growing age. Sex-related differences were estimated in children aged 6 years where girls had significantly lower selenuria than boys and girls aged 13 years had lower ioduria, magnesiuria and selenuria than boys. Women aged 18-35 years had significantly lower ioduria, calciuria and magnesiuria in comparison with men of the same age. Women have a significantly lower ioduria in comparison with men at the age 56-65 years.

INAA of serum zinc of inhabitants in five regions of the Czech Republic.

To investigate the Zn status of inhabitants of the Czech Republic, 1155 serum and 132 hair samples were analyzed for zinc content. Analyzed material was obtained from randomly selected volunteers of both sexes in the age range 6-65 yr. Subpopulations from five regions were included in the study. Analyses of both materials were performed by Instrumental Neutron Activation Analysis (INAA). Coanalyses of Standard Reference Materials (SRM) for quality control were performed. The results (mean 910 +/- 276 micrograms Zn/L serum and 189 +/- 45 micrograms Zn/g hair) demonstrate satisfactory zinc status of the searched population. Significant interregional differences and age-dependent differences, as well as sex-dependent differences have been detected by the use of correlation analysis. On the basis of these results, serum Zn concentration results of individual categories according to age and sex were evaluated, and on the grounds of mean +/- 2 standard deviations, indicative intervals were calculated. The frequency of individual serum Zn concentrations proved that the population of the Czech Republic does not suffer from severe zinc deficiency. On the other hand, about one-third of our inhabitants has their serum Zn concentrations below the cutoff value of 800 micrograms Zn/L serum, which means a marginal or mild Zn deficit of the organism.

Characterization of selenium status of inhabitants in the region Usti nad Orlici, Czech Republic by INAA of blood serum and hair and fluorimetric analysis of urine.

Selenium is an essential trace element and its insufficient status may cause serious health complications for both individuals and the whole populations. To investigate the selenium status of the subpopulation in northeastern Bohemia represented by the region Ustí nad Orlicí, 253 serum, 469 urine, and 31 hair samples from 470 randomly selected volunteers between 6 and 65 yr of age have been analyzed for selenium concentration. Serum and hair Se were detected by instrumental neutron activation analysis (means: 55 +/- 11 micrograms Se/L sera, 0.268 +/- 0.040 microgram Se/g hair). Urine Se was measured by fluorimetry (12 +/- 5 micrograms Se/L urine) with coanalyses of Lyphocheck urine, SRM Urine 2670, and Seronorm urine for quality control of the method. Results proved significant age-dependent differences, but gender differences were not significant. The frequency plot of serum Se proved maximal frequencies in adults between 55 and 70 micrograms Se/L and in children in the range 45-55 micrograms Se/L. The same plots of urine Se for both age groups showed maximal frequency in the limits 8-15 micrograms Se/L. All indices used (Se in serum, urine, and hair) confirmed mild to severe selenium deficiency in the population of the region.

[Status and selenium intake as related to the thyroid gland in the population of Znojmo]. / Stav a príjem selenu u obyvatel Znojemska a jeho vztah ke stítné zláze.

In a group of 360 people aged 6-65 years of both sexes from the Znojmo area the author investigated the selenium status and intake by serum analyses (246 cases), urine analyses (356 cases) and hair analyses (28 analyses in middle-aged men). By correlation analysis the author investigated the relationship of selenium and metabolic and peripheral thyroid parameters. From the low selenium concentration in all investigated materials (42 micrograms Se/l serum, 8.2 micrograms Se/urine, 7.2 micrograms Se/g creatinine in urine and 0.23 microgram Se/g hair) the author concludes that there is selenium deficiency in the investigated population, the primary cause being a low dietary selenium intake (average adult intake 17 to 25 micrograms Se/day). From significant, though loose correlations between selenium concentrations and thyroid parameters (size, texture, number of nodes), serum concentrations of thyroid hormones (and their ratios resp.), as well peripheral parameters of hormone actions (Achilles tendon reflex, pulse rate or anthropometric variables) the conclusion is drawn that the selenium deficiency is so marked that it interferes in the investigated population with the regulation of the organism by thyroid hormones. This effect may be caused by changes of hormone formation in the thyroid gland due to the concentration of Se-dependent peroxidase, but in particular changes of their metabolism in the circulation and periphery, as selenium participates in the active centre of deiodase I in the formation of metabolically active triiodothyronine, and selenium deficiency has an impact also on deiodase II activity in some specialized tissues.

[Changes in urinary calcium and magnesium levels during supplementation with iodine and selenium]. / Zmeny koncentrace vápníku a horcíku v moci pri suplementaci jódem a selenem.

The authors examined 31 children aged 10-13 years before and after 5-month administration of 100 micrograms iodine (as iodide 100 Merck) and 57 university students (age 18-23 years) divided into four groups. The control group of 15 students received placebo daily, 20 students took selenium (50 micrograms selenium Merck), 8 students iodine (100 micrograms iodide) and 14 students a combination of equal amounts of both elements. The authors investigated the calciuria, mangesiuria and calcium/creatinine ratio and magnesium/creatinine ratio. They found a significant drop of magnesiuria in school children after iodine intake, and in university students there was a significant drop of the magnesium/creatinine ratio in iodine and selenium treated groups as well as those who received a combination of both elements. In the latter group there was also a significant drop of the urinary calcium/creatinine ratio. The findings assembled in a relatively small group of children and students is considered preliminary. It suggests, however, the possible influence of supplementation with iodine and selenium in commonly used amounts on calcium and magnesium excretion. Changes in the control group may be due to seasonal influences.

Correlations between parameters of body selenium status and peripheral thyroid parameters in the low selenium region.

The following were measured in 380 male and female inhabitants of Prague (n the age range 6-65 years):selenium in serum and urine, iodine in urine, thyroid-stimulating hormone, thyroid volume, thyroxine (T4), triiodothyronine (T3), ankle jerk time, pulse rate and body fat. Correlations were calculated to assess the influence of Se upon the thyroid hormone parameters and their peripheral effects in Se-deficient regions both by using the linear correlation analysis and by using the multiple linear correlation analysis and the analysis of variance. Many significant linear correlations were found for whole groups of examined persons, for the individual groups (boys, men, girls and women) as well as for subgroups, according to the age and sex. We conclude, from the analytical results of Se indices (serum, hair, urine) reported previously, and on the basis of the statistical demonstration of the influence of selenium upon thyroid hormone levels and the peripheral effects in the group of Prague inhabitants in connection with the previously documented role of Se in pathways resulting in the synthesis of physiologically active thyroid hormone, that inhabitants of Prague are selenium deficient. Concurrent deficiency of selenium may modify and even worsen iodine deficiency disorders of various stages. Multiple linear correlation analysis followed by analysis of variance of subgroups indicated a coincidence of the effects of some measured parameters upon the peripheral manifestation of thyroid hormone state as well as highlighting the effect of other independent variables of thyroid hormone metabolism than those measured in the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of selenium supply and status of inhabitants in three selected rural and urban regions of the Czech Republic.

Blood serum selenium of 65 men and hair selenium of 77 men from three regions of the Czech Republic (CR) were analyzed by neutron activation analysis, and 202 samples of urine from the same populations were analyzed for Se by the fluorimetric method to assess selenium status of these regions. Low status (53 micrograms Se/L of serum and 0.29 micrograms Se/g lyophilized hair as means) and very low urine selenium (8.7 micrograms/L urine) were detected. By these data, the CR is among the countries with the lowest Se intake. A comparison of studied regions is presented. Moreover, values of serum zinc were within the reference range, but mild to moderate deficiency in the supply of iodine was detected.

Levels of some trace elements in serum of Prague inhabitants measured by INAA.

Sera of 240 randomly selected Prague inhabitants of both sexes from ages 6 to 65 yr were analyzed by instrumental neutron activation analysis (INAA) for Fe, Zn, Se, Rb, Cs, and Sc. Significant differences were found between serum Fe and Zn levels of men from Prague and from rural regions of Central Bohemia. Concentration of Se was one of the lowest in Europe and exhibited age-dependent, but not sex-dependent changes. Age-dependent changes of serum concentrations were also found for Rb, Cs, and Sc, whereas sex-dependent changes were detected for Zn, Rb, Cs, and Sc.

Selenium and rubidium changes in subjects with pathologically altered thyroid.

Concentrations of selenium and rubidium in groups of subjects with hyperthyroidism, carcinomas, or adenomas and in controls were determined by neutron activation analysis with coirradiated inorganic standards and IAEA reference material. Se was decreased in all pathological groups with the greatest modification in thyroids with carcinomas. Rb was elevated in all pathological groups with the greatest increase in carcinomas as well. According to the literature, Se has a protective effect on carcinogenity as well as on biochemical pathways in thyroid cells. There are no data in the literature on the effects of Rb in those cells. On the grounds of the present results, it seems possible to use the trapping of Rb for diagnostic purposes in cases of pathologically altered thyroids.

Biosynthesis of cholesteryl 14-methylhexadecanoate in the liver of rats bearing transplantable tumors and during chemical carcinogenesis.

Biosynthesis of cholesteryl 14-methylhexadecanoate, cholesteryl palmitate and cholesteryl stearate was studied in the liver of rats bearing the Walker 256 carcinoma. Zajdela hepatoma and during chemical carcinogenesis following the administration of benzo[a]-pyrene. An up to 9-fold enhanced production of all these esters was found in liver homogenate during the 10--16th day after Walker tumor transplantation. Only the enzyme system esterifying cholesterol in the cytosol at pH 6.5 was stimulated while the activity of similar enzymes in mitochondria, microsomes and cytosol at an acid pH were not affected. Activity of the cytosol enzyme esterifying cholesterol at pH 6.5 was also enhanced during the active growth of Zajdela hepatoma and during the period of chemical carcinogenesis characterized by the appearance of first palpable subcutaneous tumors. Enhanced activity of cholesterol esterifying enzymes in the liver exactly coincided with periods of elevated levels of cholesteryl 14-methylhexadecanoate in the liver and blood plasma as described earlier. An increased demand of the tumor-bearing host for this cholesteryl ester utilized as a co-factor for enhanced protein synthesis is obviously met by its stimulated production in the liver tissue.